In offshore drilling, if a severe storm alert occurs, it may be necessary to evacuate the platform. If a well is being drilled, it is preferable to store the string of drill pipe within the cased portion of the hole, rather than pulling the string to the surface and leaving it on the drilling rig. In doing so, the drill string must be pulled up sufficiently high so that it is fully contained within the cased portion of the well. A packer will be set in the annulus surrounding the drill pipe. A valve in the drill string closes the passage. The packer has a hanger mechanism that supports the weight of the drill string in the well. The portion of the drill string above the valve is retrieved.
While this technique is workable, the valve must be open while the drill string is run into the well, then closed. Closing the valve in the drill string can be a problem, particularly with floating drilling vessels.